Modulus metered fuel injection system



June 13, 1961 HoTTENRoTH 2,988,077

MODULUS METERED FUEL INJECTION SYSTEM 1 I 2 l l l l ,IH

INVENTOR.

United States Patent C 2,988,077 MODULUS METERED FUEL INJECTION SYSTEMFrederick W. Hottenroth, 2472 Overlook Road, Cleveland Heights, OhioFiled Feb. 24, 1958, Ser. No. 717,178 Claims. (Cl. 12S-140) Thisinvention relates to a fuel injection system for internal combustionengines in which the modulus of elasticity of the fuel itself is themeasuring index for the successive charges of fuel delivered to theengine during the cycles of operation thereof.

One of the biggest problems in connection With present day fuelinjection systems is the accurate metering of fuel into each cylinder sothat each cylinder receives exactly the amount of fuel required forproper proportioning to the mass of induced air under the conditionsexisting at the moment. It is also extremely desirable that the systembe responsive to changes with a minimum of time lag.

One object of my present invention is to provide a system which solvesboth of these problems and in addition is simple, both structurally andin operation, and is low in cost.

The common method of metering fuel for a fuel injection system measuresslugs of fuel and distributes them to individual cylinders throughpiping having considerable volume. The fuel is injected either directlyinto the cylinder or at the intake valve. A spring-closed nozzle isgenerally used. The measurement is generally accomplished by a variablevolume cylinder and piston pump. The slug volume is adjusted by suitablemeans affected by existing conditions.

Another object of my invention is to provide a small container orreservoir for fuel metering purposes preferably located closely adjacenteach cylinder and which reservoir has a definite volume proportionallyrelated to the modulus of elasticity of the fuel being used and to thechange in volume of such fuel as between the maximum pressure thereoffurnished by a fuel pump and the minimum pressure thereof resulting fromthe opening of a fuel admission valve from the fuel metering reservoirto the engine cylinder or its intake. To prevent undesirable additonalilow of fuel from the fuel pump, a restriction is placed in the lineleading from the fuel pump to the fuel metering reservoir, preferablyjust ahead of the reservoir.

A further object is to provide a fuel injection system in which the fuelcharge is essentially dependent upon the fuel pressure so that byregulation of the fuel pressure it is possible to regulate the amount offuel charge in response to existing conditions.

Still a further object is to provide a system in which the pressure in afuel manifold is regulated by a by-pass type of regulator which itselfis automatically varied to meet fuel requirements in response to manualcontrol to change the speed of the engine modified by other factors suchas air charge density, mass air flow, rich start mixture, rich idlemixture, rich mixture to obtain maximum power at full load operationand/or full throttle operation, acceleration and control associatedtherewith to prevent a momentary lean mixture condition upon suddenopening of the engine controlling throttle, fuel cut-off duringdeceleration, barometric pressure, ambient temperature and the like.

An additional object is to provide means in the system to permit use oflower pressures for the same size of container by the inclusion in thefuel metering reservoir of a material such as foam rubber, a rubber bagfilled with air or the like, which has a lower modulus of elasticitythan the fuel.

2,988,077 Patented .lune 13, 1961 ICC A final object is to provide amodulus metered fuel injection system wherein fuel is supplied underpressure to a cylinder of an internal combustion engine and means isprovided for controlling the fuel from the supply comprising a fuelmetering reservoir having a volume substantially equal to the change insuch volume divided by the product of the modulus of elasticity of thefuel being used and the change in pressure of such volume, a restrictionbeing provided between the fuel supply and the fuel metering reservoir,a fuel admission -valve being provided between the `fuel meteringreservoir and the cylinder, and means being provided which is cyclicallyoperable `for opening the fuel admission Valve.

With these and other objects in view, my invention consists in thecombination of elements constituting my modulus metered fuel injectionsystem, whereby the objects above contemplated are attained, ashereinafter more fully set forth, pointed out in my claims andillustrated in detail on the accompanying drawing, wherein:

FIG. l is a diagrammatic view of a modulus metered fuel injection systemembodying my invention;

FIG. 2 is a diagrammatic view of an internal combustion engine with afuel metering reservoir, fuel admission valve and a restriction of mysystem, shown in conjunction therewith;

FIG. 3 is a diagrammatic view illustrating the metering action of thefuel metering reservoir of my fuel injection system;

FIG. 4 is a similar diagrammatic View showing a modication of the fuelmetering reservoir and the action involved; and

FIG. 5 is a diagrammatic view showing another modiiication of my systemin which a restriction for fuel flow consists of a fuel shut-off valve.

On the accompanying drawing, I have used the reference character FT toindicate a fuel tank from which a fuel pump FP pumps fuel through afilter F to a fuel manifold FM. The pressure of the fuel in the manifoldFM is regulated by a pressure regulator PR of the by-pass type. Conduits10, 12 `and. 14 convey the fuel from the fuel tank FT to the fuelmanifold FM and return conduits 16 and 18 convey the by-passed fuelcontrolled by the pressure regulator PR from the fuel manifold FM backto the fuel tank FT.

The system is shown in FIG. l as connected with a four cylinder internalcombustion engine, the cylinders of which are indicated at C1, C2, C3and C4. Conduits 2t), 22, 24 and 26 lead from the fuel manifold FM tofuel metering reservoirs FMR and a restriction R is located ahead ofeach reservoir. The reservoirs communicate with fuel admission valvesFAV terminating in nozzles N directed into the respective cylinders orinto the intake manifold adjacent the intake valves for the cylinders.An alternative arrangement is shown in my copending application SerialNo. 725,384, tiled March 3l, 1958, now Patent No. 2,924,207, whereinthere is one fuel metering reservoir for all cylinders of an engine andthe fuel admission valve is also a distributor valve.

In operation, fuel pressure is built up in the system by operation ofthe fuel pump FP as from an electric motor M and this pressure extendsthroughout the elements 12, F, 14, FM, 16, 20, 22, 24, 26, R, FMR andFAV of the system. The pressure, of course, must be built up in eachfuel metering reservoir FMR between the successive fuel injection cyclesthereof, and the restrictions R (in the nature of conduits withcapillary bores or pierced diaphragms in which the perforations are onlya few thousandths of an inch in diameter) are calculated to take thisinto consideration. The fuel in each reservoir FMR is compressed anamount proportional to the applied pressure. This compressed fuel isheld captive in the reservoir FMR until the fuel admission valve FAV isopened whereupon a change of fuel is injected into the engine cylinderbecause of the expansion of the fuel in the fuel metering reservoir. Thequantity of the charge of fuel injected is essentially equal to thevolume change of the fuel resulting from the effect of the pressurechange on the compressibility of the liquid. There will be a smalladditional amount of fuel delivered because of the flow of fuel throughthe restriction R while the Valve FAV is open but this is negligiblebecause of the small size of the restriction and the Valve being openfor only a short period of time.

To illustrate the Kfuel metering action, reference is made to FIG. 3wherein the fuel metering reservoir FMR has volume V represented by thearea of a rectangle b, c, f, e and Vc (rectangle a, b, d, e) representsa change in volume so that V plus Vc is the total volume of fuel whennot under pressure and V is the volume thereof when under pressure. Whenthe fuel admission valve FAV is opened, the compressed fuel in FMRexpands and displaces the quantity Vc into the engine cylinder.

Assume the fuel to be gasoline. Gasoline has a compressibiility factorwhich gives a reasonable size volume for the reservoir FMR. A typical8-cylinder gasoline engine consumes about .005 cubic inch per cycle percylinder at 2,000 r.p.m. which decreases to about .004 cubic inch percycle at 500 rpm., and also at 4,000 r.p.m. it decreases to about .004cubic inch. A pressure of 1,000 p.s.i. compresses gasoline `0.7 percentor .007 of its original volume. Therefore, using the average figure of.005 for calculations, a volume of reservoir necessary to compressgasoline this amount would be 0.7 cubic inch at each cylinder. In otherwords, a reservoir having a volume of `0.7 cubic inch and fuel that iscompressed `0.7 percent by 1,000 p.s.i. results in the calculation .7.007 which gives an answer of approximately .005 which is needed as thecubic inch per cycle per cylinder requirement. This can be stated as anequation,

as follows:

VE V K Pc in which I/:volume of fuel metering reservoir Ver-desiredchange in volume of fuel K=modulus of elasticity of the fuel, andPc=change in pressure of volume V which can be worked out as-ao-Xl000=%g==approximately .7 ou. in.

The value .000007 (modulus) is the Vchange in volume per unit volume persquare inch.

Referring to FiG. 4, if a compressible body B is placed in the fuelmetering reservoir, the volume of the reservoir can be reduced inverselyproportional to the modulus ratio of such body to gasoline. The body Bmust, of course, have a lower modulus of elasticity than the gasolineand sponge rubber is suitable for this purpose. The volume of the body Bis indicated as V1 (the entire solid line circle) whereas an appliedpressure may reduce the volume to V2 (the small dotted circle). Thecompressed volume of the fuel equals the sum of the two Volumes to becompressed. One of these is the Volume of the body B and the other isthe volume of the difference between the volume of the reservoir FMR andthe body B. This sets up an equation as follows:

K V, Pc KP.,

V: KPDL K in which K1=Modulus of elasticity of compressible body, andV1=Initial volume of compressible body In my system it will be notedthat the fuel charge is essentially dependent upon the fuel pressure.Therefore, by regulation of the fuel pressure it is possible to regulatethe size of fuel charges to match existing conditions. Primarily thisregulation may be done at the fuel manifold FM by the pressure regulatorPR, by electric variation of the energization of the pump motor M, or byany other suitable means.

The pressure in the fuel manifold FM is regulated by the regulator PRwhich in itself may be automatically varied to meet fuel conditionrequirements by a diaphragm 28 which, in addition to sensing thepressure in the line 16 to provide automatic pressure regulation ofby-pass type, senses air intake manifold conditions (AIM in FIG. 1)which in turn are varied by foot acceleration position by reason of theaccelerator controlling a butterfly valve for the intake to the enginecylinder. The action of the pressure regulator may be modified by otherfactors such as rich start mixture, fast idle throttle, barometricpressure, etc. These modifying conditions are indicated RSM, FlT and BPrespectively in FIG. l.

During the operation of the system the fuel passes through therestriction R and builds up pressure in the fuel metering reservoirs FMRuntil it reaches the manifold pressure value before it is time to openthe valve FAV. This valve opens during the intake stroke of the enginepiston shown at 30 in FIG. 2 in the cylinder C1. For instance, it may beopened by a push rod 31 actuated by a cam 32 on the intake cam shaft 34which also actuates the intake valve 36 of the engine. When the pressureof the fuel held in the metering reservoir FMR is released, the fuelexpands and the volume of expansion is discharged through the nozzle N.Shortly thereafter the valve FAV is reclosed and pressure again buildsup in the container FMR as the fuel is admitted through the restrictionR.

Alternate `arrangements may be used based on the same basic operatingprinciple that the modulus of elasticity of the fuel itself is themetering characteristic of the system. Instead of a restriction R as inFIG. l, a fuel shut-off valve FSV may be used as shown in FIG. 5 whichcloses before the valve FAV opens and reopens after the valve FAVrecloses. A desired quantity of fuel is thus held captive in thereservoir FMR between the closing of the valve FSV and the opening ofthe valve FAV. This makes a system which yis theoretically correctvolume-wise since it eliminates the ow through the restriction R duringthe charge period of the reservoir FMR, and it also eliminates the smallhole of the restriction R which is subject to clogging during operationin case the fuel is dirty.

Some changes may be made in the construction and arrangement of theparts of my modulus metered fuel injection system without departing fromthe real spirit and purpose of my invention, and it is my intention tocover by my claims any modified forms of structure or use of mechanicalequivalents which may reasonably be included within their scope.

I claim as my invention:

1. A modulus metered fuel injection system comprising means forsupplying fuel under pressure to a cylinder of an internal combustionengine, and means for controlling the fuel from said first meanscomprising a fuel metering reservoir, means for restricting the ow offuel from said fuel supply to said fuel metering reservoir, a fueladmission valve between said fuel metering reservoir and the enginecylinder, and means for opening said fuel admission valve each cycle ofoperation of the engine, said fuel metering reservoir having a normalvolume so related to the change in such normal volume under an appliedpressure from said means for supplying fuel under pressure through saidrestricted means, to the modulus of elasticity of the fuel land to thechange of such applied pressure that when pressure held captive in saidreservoir between said restricting means and said fuel admission valvewhen closed is released by opening of said fuel admission valve, acharge of fuel will be discharged to the engine cylinder which chargehas a volume that is the difference between the normal volume of saidreservoir and such normal volume under said applied pressure.

2. A modulus metered fuel injection system comprising means forsupplying fuel under pressure to a cylinder of an internal combustionengine, and means for controlling the fuel from said lirst meanscomprising a fuel metering reservoir, means for restricting the flow offuel from said fuel supply to said fuel metering reservoir, said meanscomprising -a fuel shut-off valve, a fuel admission valve between saidfuel metering reservoir and the engine cylinder, and means forsequentially closing said fuel admission valve before opening said fuelshutoff valve and then closing said fuel shut-off valve before openingsaid fuel admission valve each cycle of operation of the engine, saidfuel metering reservoir having a normal volume so related to the changein such volume under an applied pressure from said means for supplyingfuel under pressure through said fuel shutoff valve, to the modulus ofelasticity of the fuel and to the change in such applied pressure thatwhen pressure held captive in said reservoir between said fuel shut-olfvalve and said fuel admission valve when both are closed is released byopening of said fuel admission valve, a charge of fuel will bedischarged to the engine cylinder which charge has a volume that is thedifference between the normal volume of said reservoir and such normalvolume under said applied pressure.

3. A modulus metered fuel injection system comprising means forsupplying fuel under pressure to a cylinder of an internal combustionengine, and means for controlling the fuel from said first meanscomprising a lfixed volume fuel metering reservoir hav-ing a volumeequal to that required for the difference between the volume off fuel insaid reservoir under an applied pressure yand the volume of fuel thereinunder the pressure at which a charge thereof is released Ito thecylinder to be the only volume constituting such charge, means forrestricting the ow of fuel from said fuel supply to said fuel meteringreservoir, a fuel admission valve be` tween said fuel metering reservoirand said cylinder, means cyclieally operated for opening said fueladmission valve, and means to vary the applied pressure to change thevolume of the fuel charge to meet engine requirements.

4. A modulus metered fuel injection system comprising means forsupplying fuel under pressure to a cylinder of an internal combustionengine, and means for controlling the fuel from said first meanscomprising a fixed-volume fuel metering reservoir having a volume equalto that required for the difference between the volume of fuel in saidreservoir under an applied pressure and the volume of fuel therein underthe pressure at which a charge thereof is released to the cylinder to bethe only volume constituting such charge, means for restricting the flowof fuel from said fuel supply to said fuel metering reservoir, saidmeans comprising a fuel shut-olf valve, a fuel admission valve betweensaid fuel metering reservoir and said cylinder, means cyclicallyoperated for closing said fuel admission valve before opening said fuelshut-off valve and for closing said fuel shut-off valve before openingsaid fuel .admission valve, and means to vary the applied pressure tochange the volume of the fuel charge to meet engine requirements.

5. A modulus metered fuel injection system comprising means forsupplying fuel under predetermined pressure to a cylinder of an internalcombustion engine, and means for controlling the fuel from said firstmeans comprising a rst valve and a fixed-volume fuel metering reservoirin which ythe fuel is compressed to said predetermined pressure and thentrapped by said first Valve, and a second valve opened in n'med relationto the operating cycles `of the engine for releasing only thedifferential volume of the compressed and trapped fuel to the enginecylinder, which differential volume is the difference between the volumeof fuel in said reservoir when at said predetermined pressure and thevolume thereof when said second valve is open to the engine cylinder andthe pressure has equalized with that in the cylinder.

6. A modulus metered fuel injection system according to claim 5 in whichsaid fixed-volume fuel metering reservoir has therein a compressiblebody of material that has a lower modulus of elasticity than the fuel.

7. A system for modulus metering liquid to a liquid receiver, whichsystem measures individual charges of the liquid, comprising afixed-volume chamber, an inlet valve leading thereto, an outlet valveleading therefrom to the receiver, means for pumping liquid through saidinlet valve into said chamber and compressing the liquid therein, meansfor closing said inlet valve and then opening said outlet valve so thequantity of liquid metered to the receiver is equal only to thedifference between the volume of the liquid in said fixed-volume chambercompressed by the inlet pressure and the volume of the liquid in thechamber when the liquid is permitted to expand by its reduction inpressure to the pressure in the receiver.

8. A modulus metering system for delivering liquid comprising means `forsupplying liquid under predetermined pressure to `a point of consumptionthereof, and means for controlling charges of liquid from said firstmeans comprising a fixed-volume liquid metering reservoir in which theliquid is compressed and `trapped to said predetermined pressure, and -avalve associated With said reservoir for releasing a portion only of thecompressed and trapped liquid to said point of consumption when saidvalve is opened, said portion being the differential volume of liquidcompressed in said chamber compared to such liquid when decompressed byopening of said valve.

9. A modulus metered fuel injection system according to claim 2 .andincluding a compressible body of material in said fuel meteringreservoir having a lower modulus of elasticity than the fuel.

10. A modulus metered fuel injection system according to claim 4 inwhich said fuel metering reservoir has therein a body of lower elasticmodulus than the fuel.

References Cited in the file of this patent UNITED STATES PATENTS1,919,601 Simmen July 25, 1933 2,420,550 Miller May 13, 1947 2,453,196Clark Nov. 9, 1948 2,576,451 Dickson et al Nov. 27, 1951 2,592,132Feilden et al. Apr. 8, 1952 2,747,555 Brunner May 29, 1956 2,825,396Greer et al Mar. 4, 1958

